Polyethylene Vinyl Acetate (EVA), a versatile thermoplastic copolymer, is renowned for its exceptional flexibility, impact resistance, and superior adhesion properties, making it a preferred material across industries such as footwear, packaging, solar energy, medical, and construction.
Available in granule or film form, EVA boasts excellent electrical insulation, UV resistance, and ease of processing, making it ideal for producing soft, lightweight, and durable products. The material’s properties vary based on the Vinyl Acetate (VA) content, ranging from 5% to 40%, allowing it to transition from rigid plastic-like behavior to rubber-like elastomeric characteristics.
Tolymer supplies high-quality EVA in various grades, tailored to meet manufacturers’ needs with a focus on performance, sustainability, and cost-efficiency. By enhancing product durability and reducing production costs, EVA delivers significant value to industrial and consumer applications.
Polyethylene Vinyl Acetate stands out for its unique combination of flexibility, durability, and environmental resistance, playing a pivotal role in both consumer and industrial products.
With high toughness, good transparency, and weather resistance, EVA serves as a cost-effective alternative to traditional materials like rubber and PVC in numerous applications. Its key applications include:
– Footwear Industry: Soles and insoles for athletic and casual shoes, requiring flexibility and impact absorption.
– Solar Energy: Protective films for solar cells, demanding UV resistance and transparency.
– Packaging: Stretch films and food packaging, needing adhesion and flexibility.
– Medical: IV bags and medical equipment, requiring safety and flexibility.
– Construction: Thermal and acoustic insulation foams, prioritizing lightweight and durability.
EVA enhances product comfort, safety, and longevity, enabling manufacturers to produce competitive, high-quality goods.
Base Polymer: Copolymer of ethylene and vinyl acetate, with VA content ranging from 5% to 40%, determining flexibility and elastomeric properties.
#### Base Additives
– Antioxidants and UV Stabilizers: Prevent degradation during processing and long-term use, ensuring product longevity.
UV Stabilizers: Enhance resistance to sunlight for outdoor applications, validated per ASTM G154.
– Plasticizers: Adjust flexibility in low-VA grades for tailored performance.
– Fillers: Such as calcium carbonate, reduce costs and enhance strength in economical grades.
– Specialty Additives: Include flame retardants for safety (UL 94 V-0 compliant), pigments for aesthetics, and biocompatible additives for medical applications meeting FDA and REACH standards.
Properties: Higher rigidity (plastic-like), tensile strength up to 20 MPa, and excellent processability with Melt Flow Index (MFI) of 2-5 g/10 min. Ideal for applications requiring moderate flexibility and strength.
– Applications: Industrial packaging films, cable coatings, and injection-molded parts. Example: Pallet wrap films.
Properties: Balanced flexibility, good impact resistance, and high transparency. Suitable for applications needing a balance of rigidity and softness.
– Applications: Athletic shoe soles, solar cell encapsulant films, and insulation foams. Example: Running shoe soles with shock absorption.
Properties: Rubber-like elastomeric properties, excellent flexibility, and high adhesion. Ideal for soft, stretchable products.
– Applications: Comfort shoe foams, medical IV bags, and hot-melt adhesives. Example: Orthopedic shoe insoles with high softness.
Properties: Contains UV stabilizers to resist sunlight degradation, preventing yellowing and maintaining properties for up to 5 years outdoors (ASTM G154 validated).
– Applications: Solar panel encapsulant films, outdoor coatings, and agricultural equipment. Example: Protective layers for solar panels.
Properties: Meets UL 94 V-0 standards, ensuring high fire safety while retaining flexibility. Suitable for safety-critical applications.
– Applications: Cable coatings in buildings, electrical components, and industrial insulation. Example: Electrical cable insulation in facilities.
Properties: Free of toxic substances, compliant with FDA and REACH standards, offering flexibility and safety for human contact.
– Applications: Medical IV bags, tubing, and hospital equipment. Example: Hospital IV fluid bags.
Properties: Lightweight cellular structure with density of 0.1-0.3 g/cm³, excellent thermal and acoustic insulation, and high impact absorption.
– Applications: Building insulation foams, sports mats, and shoe insoles. Example: Yoga mats with softness and durability.
Soles (Medium VA): Used in athletic and casual shoes for flexibility and shock absorption.
– Orthopedic Insoles (High VA and EVA Foam): Provide comfort and durability for sports and medical footwear. Example: Running shoe insoles.
– Solar Cell Encapsulant Films (UV-Resistant): Offer transparency and UV resistance to extend solar panel lifespan, improving efficiency and durability.
– Stretch and Packaging Films (Low VA): Provide adhesion and flexibility for food and industrial packaging, ensuring product safety. Example: Food packaging films.
– IV Bags and Tubing (Biocompatible): Deliver flexibility and safety for hospital applications, enhancing medical device performance.
– Thermal and Acoustic Foams (EVA Foam): Lightweight and durable, reducing energy consumption in buildings. Example: Floor insulation panels.
Polyethylene Vinyl Acetate is an ideal choice for industrial and consumer applications due to its versatile properties. Key advantages include:
– High Flexibility: With VA content up to 40%, EVA ranges from plastic-like rigidity to rubber-like softness, perfect for shoe soles and medical bags.
– Impact Resistance: High toughness (up to 50% elongation at break) makes EVA suitable for protective foams and shoe soles.
– Electrical and Thermal Insulation: With electrical resistivity up to 10¹⁴ ohm-m and low thermal conductivity (0.02 W/m·K), EVA is ideal for cable coatings and building insulation.
– Environmental Resistance: UV-resistant grades withstand sunlight for up to 5 years, suitable for solar films and outdoor applications.
– Ease of Processing: MFI of 2-20 g/10 min and processing temperatures of 160-200°C enable fast extrusion and molding.
– Excellent Adhesion: High-VA grades offer inherent adhesion, ideal for hot-melt adhesives and packaging films.
– Cost-Effectiveness: Up to 30% cheaper than traditional rubbers, reducing production costs in footwear and packaging.
– Biocompatibility: Medical-grade EVA, compliant with FDA standards, ensures safety for medical devices.
Despite its advantages, Polyethylene Vinyl Acetate has limitations that manufacturers should consider:
Limited Mechanical Strength: Tensile strength (up to 20 MPa) is lower than polymers like PP, limiting use in high-load applications.
– Low Heat Resistance: Softens above 70°C, unsuitable for high-temperature environments like engine components.
– Solvent Sensitivity: Low resistance to organic solvents (e.g., gasoline), restricting use in chemical environments.
– Higher Cost for Specialty Grades: UV-resistant and biocompatible grades can be up to 20% more expensive, impacting cost-sensitive applications.
– Flammability: Without flame-retardant additives, EVA is flammable, requiring modification for safety-critical uses.
– Complex Recycling: Due to varying VA content and additives, recycling is more challenging than for simpler polymers like PE.
– Additive Dispersion Issues: In filled grades, poor additive dispersion may cause surface defects.
– Moisture Absorption: Up to 0.1% moisture absorption may cause minor property changes in humid environments.
Proper storage of Polyethylene Vinyl Acetate is critical to maintain its physical properties and processability:
– Temperature Control: Store at 15-25°C to prevent granule sticking. Temperatures above 30°C may degrade additives.
– Moisture Protection: Moisture levels above 0.1% can cause surface defects. Use laminated polyethylene bags (100-micron thickness).
– UV Protection: UV exposure degrades additives. Store in covered areas using opaque bags.
– Stacking Guidelines: Stack bags on dry pallets, up to 5 bags high, with 50 cm spacing for ventilation.
– Periodic Checks: Monitor temperature, humidity, and bag condition. Follow FIFO (First In, First Out) to prevent quality loss.
Proper packaging and transportation ensure EVA quality and prevent contamination:
– Robust Packaging: Use 25 kg laminated bags or 500-1000 kg big bags with polyethylene liners for moisture protection.
– Accurate Labeling: Durable labels with safety instructions (e.g., “Keep away from sunlight”) and technical specs, per ISO 780.
– Safe Transport: Use clean, ventilated vehicles. Cooling containers (below 30°C) are recommended in warm seasons.
– Load Stability: Symmetrical bag stacking with secure straps on standard 1000 kg pallets.
– Regulatory Compliance: Transport per ADR regulations, with MSDS and quality certificates provided.
Manufacturing with Polyethylene Vinyl Acetate may encounter challenges:
– Process Adhesion: High viscosity in high-VA grades causes sticking to equipment. Lubricants and temperature control (160-200°C) mitigate this.
– Moisture Absorption: Moisture above 0.1% causes bubbles or surface defects. Dry granules at 60°C for 2 hours.
– Poor Additive Dispersion: Inadequate filler dispersion reduces mechanical properties. High-shear mixers resolve this.
– Unexpected Shrinkage: Thick parts may shrink due to uneven cooling. Proper mold design and cooling control prevent this.
– Thermal Degradation: Processing above 200°C degrades the polymer. Adhere to recommended temperatures.
– Low Melt Flow: Low MFI in high-VA grades may cause incomplete mold filling. Select appropriate grades.
Selecting high-quality Polyethylene Vinyl Acetate is essential for durable products:
– VA Content: Low VA for rigidity, high VA for flexibility. Match grade to application (e.g., footwear or medical).
– Mechanical Properties: Verify tensile strength (minimum 15 MPa) and elongation at break. Request technical data sheets.
– Environmental Resistance: UV-resistant grades should be ASTM G154 certified for outdoor use.
– Moisture Content: Ensure moisture below 0.1% to avoid defects. Request moisture test reports.
– Melt Flow Index (MFI): MFI of 2-20 g/10 min for processability. Higher MFI suits films.
– Safety Certifications: Confirm FDA, REACH, or RoHS compliance for medical applications. Ensure no toxic substances.
– Additive Quality: Uniform dispersion of fillers and additives. Test samples are recommended.
Similarities: Both are thermoplastics with similar processing and use in packaging and insulation.
– Differences: EVA offers greater flexibility and adhesion, while PE is more rigid and cost-effective for general applications like bags.
– EVA Advantage: Superior flexibility and adhesion for stretch films and shoe soles.
– Limitation: Lower mechanical strength and higher cost than PE.
Similarities: Both are used for molded parts and packaging via extrusion and molding.
– Differences: PP has higher strength and chemical resistance, while EVA is more flexible and suited for foams and soft films.
– EVA Advantage: Better flexibility and impact absorption for footwear foams and insulation.
– Limitation: Lower heat and chemical resistance than PP.
Similarities: Both are flexible with high impact resistance, used in footwear and protective films.
– Differences: TPU offers superior abrasion resistance and durability, while EVA is cheaper and ideal for lightweight foams.
– EVA Advantage: Lower cost and easier processing for shoe foams.
– Limitation: Lower abrasion resistance than TPU in heavy-duty applications.
Similarities: Both enhance consumer product aesthetics and performance.
– Differences: Color masterbatch is added to EVA for pigmentation, while EVA is designed for flexibility and adhesion.
– EVA Advantage: Inherent flexibility and adhesion for soles and films.
– Limitation: No direct impact on color, where masterbatch excels.
Similarities: Both are used for lightweight foams in footwear and insulation.
– Differences: Foaming masterbatch creates cellular structures in polymers, while EVA has inherent foaming capability.
– EVA Advantage: Built-in foaming properties for lightweight, soft foams.
– Limitation: Requires specific additives for very low-density foams.
Polyethylene Vinyl Acetate (EVA) is a flexible copolymer used in shoe foams, packaging films, and medical equipment, offering durability and flexibility.
Footwear, solar energy, packaging, medical, and construction industries.
EVA is more flexible and adhesive, while PE is more rigid and cost-effective.
Yes, biocompatible grades meeting FDA standards are safe for medical devices.
Via extrusion or molding at 160-200°C. Dry granules at 60°C for 2 hours to prevent defects.
Flexibility, impact resistance, insulation, UV resistance, and cost-effectiveness.
Yes, but varying VA content and additives make recycling more complex.
Low VA for films, high VA for foams, and biocompatible for medical applications.
Up to 2 years under proper storage conditions.
Suitable up to 70°C. Other polymers are recommended for higher temperatures.
Test tensile strength, MFI, UV resistance, and moisture content. Review supplier reports.
Yes, its ease of processing and lower cost than rubber reduce expenses.
Low VA is more rigid; high VA is more flexible and rubber-like.
No, with proper processing and ventilation, it is odor-free.
Use lubricants and maintain processing temperatures below 200°C.
Yes, medium VA and EVA foam grades are ideal for athletic soles and insoles.